Blade securing means for frame saws



March 1, 1955 R. A. JOLIE 2,703,121

BLADE SECURING MEANS FOR FRAME SAWS Filed Aug. 21, 1955 Iawezaiofl: 1206422 8 =11 JoZl'e, & Quit W 9 1? .4... 'fflfiofl nqys United States Patent 'ce 2,703,121 BLADE SECURING MEANS FOR FRAME SAWS Robert A. Jolie, Marlboro, Mass., assignor to Parker Manufacturing Company, Worcester, Mass., :1 corporation of Massachusetts Application August 21, 1953, Serial No. 375,777 3 Claims. (Cl. 145-34) This invention relates to frame saws, and more particularly to the stud so-called, by means of which the flat blade is secured under tension to an arm of the frame, and the object is to provide a construction whereby the blade lies flat throughout its length and faced in the proper direction.

My invention will be well understood by reference to the following description of the illustrative embodiment thereof, shown by way of example in the accompany drawing wherein:

Fig. l is a side view with the central portion broken away, of a hacksaw of the frame type;

Fig. 2 is a view on an enlarged scale showing the lower portion of the rear of the frame nearer the handle and the stud carried thereby in the position which it takes when the blade is being engaged therewith;

Fig. 3 is a section on the line 3-3 of Fig. 2 on a still larger scale;

Fig. 4 is a view similar to Fig. 1, showing the position of the stud when tension has been applied to the blade; and

Fig. 5 is a section on the line 55 of Fig. 4.

I have here shown the invention applied to a hacksaw frame of the kind disclosed in the patent to Priest 2,292,657, October 20, 1936, the frame embodying the extensible back with front and rear arms 12 and 14 and a suitable handle 16. The front arms 12 and 14 have at their lower ends portions extended in planes perpendicular to the plane of the frame with holes therethrough to receive respectively the front and rear studs and 22 to which the blade is anchored. Herein the rear stud 22 is longitudinally adjustable to tension the blade, and the following description will relate more particularly to the construction which includes this stud.

As seen in Figs. 3 and 5 the arm 14 has an opening essentially square, having opposed flat sides in which the corresponding portion of the stud fits somewhat loosely, yet to be guided for sliding movement. As usual the stud may be removed and turned 90 degrees to provide for facing the edge of the blade laterally to the frame. Herein the square portion of the stud is formed by flattened sides on a threaded shank 24 (as if we planed off the sides of a bolt on four sides, although the studs are not in practice made by that method) leaving sufiicient thread between the flats to receive the tensioning wing nut 26 at the outer end of the stud, which cooperates with the outer wall of the arm 14 around the margin of the hole when tension is applied to the blade. At the one end of the stud there is provided a flat surface 28 on which the blade rests, the surface having, arising therefrom, an integral inclined pin 30 over which the hole in the blade is placed. The description as so far given would equally apply to a stud as shown in the patent aforesaid.

Hitherto the plane surface 28 of such a stud has been approximately in the central plane of the shank portion of the stud or parallel thereto. If the opening in the arm had long, accurately machined surfaces and the stud likewise fitted to it with a close fit of accurately machined surfaces the blade would be maintained in its desired position. However, a free movement of the stud without lubrication is required and it must be capable of being easily withdrawn and repositioned to present the plane surface 28 in different positions at right-angles one to another. Moreover, such an exact construction of the parts would not be economically feasible. Therefore, there is a certain clearance between the square of 2,703,121 Patented Mar. 1, 1955 the stud and the square of the hole, and when the wing nut 26 is set up and engages the outer wall of the arm, the stud tends to be driven by the nut and move from the position schematically shown in Fig. 3 to that shown in Fig. 5, until the squares jam one within the other to prevent further turning. Therefore, it has been necessary to hold the blade in position while the nut was set up. When so set up the blade was held tensioned by the spring of the frame in its desired position. Nevertheless, if there were play at the square the threaded member might be turned in the stationary nut and it was possible to cant the blade.

In accordance with my invention I permit and assume a certain clearance between the stud and the hole. The flats prevent free rotation and define in general the orientation of the blade in its required positions of presentation and permit the sliding movement necessary to draw on the stud and tension the blade. The angularly plane surface 28 however is offset from the central plane of the stud in an angular direction opposite to that of the advance of the thread, counterclockwise viewing Fig. 3 since the thread is right-hand.

When a blade is to be secured in a frame the tensioning nut 26 is backed off to permit the stud to be thrust inwardly (toward the left in Fig. 2) so that the blade may be easily hooked over the end of the pin 30. This is the position of Figs. 2 and 3. The nut then is set up and tension applied. The nut tends to turn the stud clockwise viewing Figs. 3 and 5 and the stud moves from the position of Fig. 3 to the position of Fig. 4, where the internal square is checked within the outer square. When this occurs the surface 28 is brought automatically to the position shown in Fig. 5, in the desired vertical plane, viewing that figure. This corresponds to Fig. 4.

, The blade is locked against displacement in a clockwise direction viewing Fig. 5 and because of the jammed relation of the squares displacement in the opposite direction is hindered. Further to oppose its being displaced counterclockwise I have here shown the threaded shank as of suflicient length to accommodate a milled cheek nut 32 at its inner end adjacent the surface 28 to lie at the inner side of the arm 14. This nut 32 may be backed off to the left, as shown in Fig. 2, sufiiciently to permit the stud to be drawn toward the right and the blade to be effectively tensioned without bringing the check nut against the inner surface of the arm. This is the position shown in Fig. 4. The check nut may now be turned down against the inner surface of the arm, as seen in Fig. 1, and a slight additional turn of the tension nut 26 will make all firm and'etfectively prevent casual rotation of the threaded shank in the nut while the saw is in use.

I am aware that the invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof, and I therefore desire the present embodiment to be considered in all respects as illustrative and not restrictive, as is in fact clear in several matters from the description itself. Reference is to be had to the appended claims to indicate those principles of the invention exemplified by the particular embodiment described and which I desire to secure by Letters Patent.

1. A stud for securing the end of a flat saw blade in a frame of the type having an arm with a hole having opposite fiat sides through which hole the stud passes, said stud having a portion having opposite flat sides to oppose those of the hole, the distance between said sides being slightly less than that between the said flat sides of the hole, and having a thread adapted to receive from one end a tensioning nut to cooperate with the outer wall of the arm at the margin of the hole to draw on the stud and also having at its other end a flat surface on which the side of the blade may rest and means for engaging the blade so positioned to be drawn on by the stud, the plane of said surface being angularly offset from a perpendicular between opposite fiat sides of the stud in a rotary direction opposite to the direction of advance of the thread to provide for positioning such surface and the blade parallel to opposite flat walls of the hole when the stud turns in the holev and jams againstthe. walls .thcreofunder stress .of.

the nut when the latter is tightened.

2. A stud as set forth in claim 1 which also carries a check nut on the thread which may be backed up against the arm tov engage with the face opposite that engaged by the tensioning nut to clamp the blade in such parallel position.

3. For a frame saw having an arm with a non-cirular opening therethrough, a stud having a portion of like contour and slightly smaller cross-sectional area to be received therein, said stud having a'thread on its outer end to receive a tensioning nut and on its inner end a fiat surface on which the side of the blade may rest and means for engaging. the blade so positioned to be drawn on by the stud, the plane of said surface 15 2,173,365

5 the hole due to the formers smaller area.

References Cited the file of this patent UNITED STATES PATENTS Priest I an. 26, 1937 1,395,511 Morgan Nov. 1, 1921 1,473,803 Adell et a1. Nov. 13, 1923 1,561,660 Peck Nov. 17, 1925 2,085,667 Macomber June 23, 1937 Kessler Sept. 19, 1939 

